1. Field of the Invention.
This invention relates to a machine capable of cutting any one of numerous sizes of disposable containers such as plastic bottles and/or metal cans into small pieces.
2. Description of the Prior Art.
Recent legislation regulating the collection and disposition of disposable containers such as plastic bottles and metal cans in the soft drink industry has resulted in increased interest in machines that can be employed to reduce the size of the used containers to simplify handling and storage. Two recently devised machines have been primarily successful in satisfying these objectives.
The first of these machines is of a type which is intended to cut a large number of containers simultaneously and is disclosed in U.S. Pat. No. 4,729,515 entitled "Machine For Cutting Disposable Containers", issued on Mar. 5, 1988 to John W. Wagner and incorporated by reference herein. This machine is intended to be operated by operating personnel at a container collecting facility such as a grocery store or the like. For example, depending on the sizes of the plastic bottles, twenty to forty plastic bottles can be initially loaded in the upper loading section of the machine. When the top of the loading section is closed, the machine can be turned on to cause the bottles to be cut in a centrally located cutting section. The cutting section includes a pair of parallel shafts mounted for rotation in opposite directions with each shaft having a plurality of cutting wheels mounted for rotation thereon. The cutting section cuts the containers into plastic strips or pieces which are then collected at a collecting section therebelow.
The second of these machines is employed to separately cut individual bottles as they are separately fed to a "reverse vending machine". A reverse vending machine is a machine which is installed in grocery stores or the like for customers to directly deposit plastic bottles or metal cans therein. At the same time the machine cuts the container into small pieces to decrease the overall volume of plastic or metal collected therein, the customer receives a token or other redemption of a deposit paid when the soft drink or other beverage was initially purchased. Such a machine is disclosed in U.S. Pat. No. 4,669,673 entitled "Apparatus For Cutting Disposable Containers", issued on Jun. 2, 1987 to Frank J. Lodovico and John W. Wagner and incorporated by reference herein. This machine utilizes a first cutting section similar to that disclosed in U.S. Pat. No. 4,729,515 but also includes a second cutting section to transversely cut the elongated strips as they are being discharged from the first cutting section in order to produce smaller pieces. The production of smaller pieces means that a greater number of plastic bottles can be cut for the same volume of the collecting section. In other words, cutting into the smaller pieces reduces the overall volume of material requiring less frequent attention by the store personnel and greater savings in space for future transportation.
Clearly, with such a machine it is essential for the containers to be continuously fed for cutting without any jamming or failure. In fact, to insure that a customer will not deposit a container in the machine prior to proper cutting of the immediately preceding container, the machine includes sensing devices to determine that each container passes by the entrance for proper cutting in the cutting section. As a result, any failure or delay in cutting could cause complete loss of the machine to subsequent customers wishing to redeem containers until the machine is cleared by store personnel. To insure proper feeding, an improved, reliable feeding system is taught in U.S. Pat. No. 4,703,899 entitled "Feeding Device For A Container Cutting Machine" issued on Nov. 3, 1987 to Frank J. Lodovico and incorporated by reference herein.
Because of the reduction of volume created by the smaller pieces, it is clear that there remains a need for any machine which can effectively cut disposable containers into small pieces. While the machine of U.S. Pat. No. 4,669,673 is extremely reliable and effective, the machine does require a second cutting section including additional cutting elements and an additional drive system. Any means which could be employed to eliminate these elements while still producing the more desired smaller pieces of the disposable container would clearly be attractive. With the overall reliability and satisfaction of the basic container cutting machine, it would seem desirable to find some means for adding additional cutting capabilities within the basic machine so that the second cutting section of the machine taught in U.S. Pat. No. 4,669,673 might be unnecessary.
If fact, that are a number of machines utilized in the paper, cardboard, or sheet material cutting art which produce a basic cutting at the edges of cutting discs or wheels and employ other means for producing a transverse cut of the material therein to produce smaller pieces rather than pieces in a strip form. All of these machines seem to employ a cutting section which includes a pair of parallel shafts mounted for rotation in opposite direction. The pair of shafts each support a plurality of cutting wheels for rotation therewith. Each of the cutting wheels mounted on one of the shafts is spaced from axially adjacent cutting wheels on the same shaft to closely receive one of the cutting wheels on the other shaft therebetween. Although these prior art devices employ the same overall configuration, the design of the cutting teeth or cutting surfaces on the cutting wheels are different. In each case the particular shape is intended to produce a transverse cut which results in the elongated strips being cut into smaller pieces as they pass between the rotating cutting wheels.
U.S. Pat. No. 3,860,180 entitled "Method And Apparatus For Destroying Documents" is intended to cut sheet paper material into elongated strips which are then transversely cut into smaller pieces. Specifically, the cutter rollers include a series of helically formed notches. The pointed trailing edge of each notch of the rotating rollers intersects or overlaps the outer periphery of the rollers on the other shaft during their rotation. Since the notches are helically formed, the helical angle should make propagation of the transverse cut of the paper material easier. However, a similar notch configuration would not be effective for the stiffer and tougher plastic material of bottles or metal of cans. Basically, with the formation of the initial edge cuts, those formed at the edges of the rollers, continued propagation of such edge cuts is likely as the strips are being formed. In other words, once edge cuts are produced, further propagation of the tougher plastic or metal of cans is likely so that only strips would be formed as the pointed edge of the trailing portion of the notch simply pushes rather than transversely cuts the stiffer and tougher material. FIG. 3 of U.S. Pat. No. 3,860,180 proportedly discloses the type of cutting produced by the machine. However, as will be seen in the Detailed Description hereinbelow, the actual cutting produced would be different for paper and, it is expected, that a transverse cut would not even be produced for the heavier, stiffer material of the disposable containers.
U.S. Pat. No. 4,260,115 entitled "Document Shredder" discloses a machine which again utilizes the basic cutting configuration and is intended to cut sheet waste material such as paper, cardboard, micofilm, plastic, rubber and leather. Again there is initial cutting at the edges of the discs in a direction corresponding to the movement of the sheet material through the cutters. Continued movement of the strips causes them to be pinched or cut transversely of the initial edge cuts between an engaging edge of a facing spacer member and the peripheral edge of the teeth of the cutting disc. However, there is no explanation of how more than one sheet might be cut and no explanation of how long the tolerances of this type of cutting disc can be maintained. It is expected that wear and tear of the edges would be significant for the tougher, thicker plastic or metal material of the disposable containers. It is clear from experimentation that thicker wall material as found in plastic bottles and metal cans could not be cut in this manner.
U.K. Pat. No. 2,118,065 A entitled "Waste Material Shredder" discloses a machine which is clearly intended to cut sheets of paper or cardboard as evidenced by the narrow gap between the spacer plates at the entrance to the cutting area. In order to produce a transverse cut in this machine, there is provided a leading face of a protrusion on one cutter disc which acts to guide the waste sheet material toward a tooth of the opposite cutter disc. The direction of relative movement is substantially perpendicular one to the other so that the point of the tooth is perpendicular to the sheet material. This proportedly produces a transverse cut of the sheet material. While such a transverse cut may occur with the thin, relatively weak sheet material to be used in this machine, it is not expected that such transverse cutting could be produced in the relatively heavy plastic or metal material. Experimentation with numerous teeth of a similar orientation has resulted in propagation of the edge cuts, those initially produced at the edges of the disc, and has resulted in an early formation of the strips as the pointed end of the teeth simply pushes the material rather than penetrating it for a transverse cut.
German Offenlegungsschrift DE 33 12 173 A1 is intended to cut sheet material. It is clear that the narrow gap between the spacer plates would only permit sheet material to be directed to the cutting discs. Again, as in U.S. Pat. No. 4,260,117, there is initially edge cutting at the edges of the cutting discs in the direction of movement between the cutting discs. However, an acutely pointed tooth on the disc proportedly pierces the sheet material to produce a transverse cut which, when combined with the initial edge cut, will produce small pieces of the material. As far as the design is concerned, it is extremely difficult to expect that such acute teeth would remain sufficiently sharp to produce a transverse cut on such heavy, stiff material as is used to produce the plastic bottles and metal cans. Again, there is some doubt that such an acute tooth, even if it were to remain sharp, would produce a transverse cut in such material. It is expected that the initial elongated cut at the edges of the discs would be propagated by the impact of the tooth so that no transverse cut would really be produced. The end of the tooth could simply push the sheet material so that the edge cut would simply propagated toward the tooth to cause the strip to be formed more quickly. Once in strip form, the strips would be free to move away from the end of the tooth so that there would not be sufficent resistence to produce any transverse cut.
Finally, U.S. Pat. No. 4,625,925 entitled "Commuting Apparatus For Sheet Material Or Sheet Material Layers" discloses a machine which is intended to cut one or more sheets of paper including plastic coated paper as well as plastic foils or the like. This machine again relies on a transverse cut at the peripheral edges of the teeth of the cutting disc. The teeth on one disc of a first shaft are aligned with the gap between the teeth of the overlapped discs of the other shaft. An examination of the teeth and how they intersect or overlap one another as they rotate reveals that the leading surface of one tooth is generally perpendicular to the teeth of the overlapping discs in the same manner as the leading face of the protrusion and the teeth of U.K. Pat. No. 2,118,065. There are more teeth on the disc of U.S. Pat. No. 4,625,925 so that smaller pieces, if they are in fact produced, would be expected. However, in any case, the cutting which might be produced in any material in such a machine would not be like that disclosed in FIG. 5 therein. While it is felt that the thicker, stronger material of plastic bottles and metal cans would not be cut in such a manner as might paper in the machine of U.S. Pat. No. 4,625,925, any effort to cut transversely will produce edge cuts in a manner different from those disclosed in the patent. This fact will be further discussed in the Detailed Description hereinbelow. It is again believed that the edge cuts, such as those produced in German Offenlegungsschrift DE 33 12 173 A1, would be propagated toward the peripheral edge of each tooth. Propagation of the edge cuts would tend to release the strips and allow them to move away from the point of the tooth to prevent the desired transverse cut.
Interestingly enough, all of these prior art devices employ the basic overlapping disc configuration to produce edge cuts. Additionally, all include a tooth or transverse cutting edge which may or may not produce the claimed transverse cut of sheet material which, in most cases, is made of paper or cardboard. As will be seen, the formal disclosures in the patents of the type of cuts produced by two of these machines are incorrect. Substantial experimentation with numerous similar tooth configurations have been conducted in an effort to transversely cut the disposable containers having the heavier wall material. As a result of these experiments, it is felt that none of the designs mentioned above would produce the desired smaller pieces of the heavier and stiffer plastic or metal material.
In addition to the difference in material that may cause a different result, there is a significant difference in the material configuration that can affect the efficiency and effectiveness of the cutting process. Although the disposable containers of the present invention are formed of thin wall material, it is not in sheet form. Because of the odd shape, it is not presented to the cutting disc in an orderly and aligned manner as can the sheet forms of material disclosed in the prior art machines. It is also most significant that there will never simply be one layer of the thin wall material to be cut. Since the containers are bottles or cans, they typically must be "flattened" to be advanced between the cutting wheels. The feeding device of U.S. Pat. No. 4,703,899 tends to collapse or crush the containers to enable the teeth of the cutting wheels to grip them and draw them therebetween for cutting. Therefore, there will always be at least two layers of the thin wall material directly between the cutting wheels. In fact, since some plastic bottles are designed to include a separately formed and detached base of the plastic material, there can be as many as four layers simultaneously directed between the cutting wheels.
Still another complication exists for the cutting of disposable containers of the present invention that may not be present in the operation of any of the prior art machines. The soft drink liquid remaining in the disposable containers has been found in a short time of operation to completely engulf the interior of any container cutting machine. The liquid is extremely corrosive and the sugary substance can create even greater problems when heated. The friction created by the rotating cutting disc can produce a build up of solid, corrosive by-products that can seriously reduce the effectiveness and even the life of the machine.
Accordingly, it should not be surprising that the prior art machines for cutting sheet paper, etc., would not produce a transverse cut of several layers of thicker, heavier wall material of odd shaped articles in a sticky, corrosive environment. Any transverse cutting that these prior art machines might be able to produce in the material of the disposable containers would be limited and only for a relatively short period of operating time.